Electric circuit timing switch



April 22, 1952 c. J. CADWELL ETAL 2,593,727

ELECTRIC CIRCUIT TIMING SWITCH Filed Dec. 17, 1948 2 SHEETS-SHEET 2gvwmbo'bs' Clarence dla a u ell Fla/1k Hfidawzsan {PH WW Patented Apr.22, 1952 ELECTRIC CIRCUIT TIMING SWITCH Clarence J. Cadwell,Carpinteria, and Frank M. Adamson, Los Angeles, Calif., assignors to TheCadwell Corporation, Beverly Hills, Calif., a corporation of CaliforniaApplication December 17, 1948, Serial No. 65,896

2 Claims.

This invention relates generally to the class of circuit makers andbreakers and itis directed particularly to a device of this characterwhich is time operated.

A principal object of the present invention is to provide an improvedelectric circuit timing switch wherein novel means is provided forchanging the timing periods or operating frequency of the switch.

Another object of the invention is to provide an electric circuit timingswitch in which the timing periods may be easily and quickly changed sothat the switch may be employed for a period of time for closing acircuit at intervals of say one second and may then be employed foranother period of time for closing the circuit at intervals of a halfsecond or a quarter second or any other time frequency.

A further and more specific object of the invention is to provide acircuit controlling device in which a series of concentric constantlyrotating toothed elements is employed in association with a circuitmaking and breaking unit which is shiftably positioned adjacent to thetoothed elements whereby the unit may be brought into any one of anumber of selected positions to cause a selected one of the toothedelements to periodically actuate the switch.

A further and more specific object of the invention is to provide aneasily and quickly changed timing mechanism designed particularly foruse in association with still picture projecting machines forcontrolling the operation of the electrically operated mechanism bywhich the pictures are changed, whereby the changing of the pictures maybe made to occur at intervals of one minute, half minute, quarter minuteor any other selected interval.

The invention will be best understood from a consideration of thefollowing detailed description taken in connection with the accompanyingdrawings forming a part of the specification, with the understanding,however, that the invention is not to be limited to the exact details ofconstruction shown and described since obvious modifications will occurto a person skilled in the art.

In the drawings:

Figure 1 is a view in top plan of a projector to one side of which issecured a timer switch constructed in accordance with the presentinvention.

Figure 2 is a view in front plan of the timer switch structure.

Figure 3 is a view in side elevation of the same.

Figure 4 is a sectional view taken substantially on the line 4-4 ofFigure 2,-the parts to the rear of the body plate being omitted.

Figure 5 is a detailed section taken substantially on the line 5-5 ofFigure 3.

Figure 6 illustrates the circuit diagram for the mechanism.

Figure 7 is a section on the line 1-1 of Figure 2 through the switchsupporting cradle and the lever, the body of the switch being inelevation.

The electric circuit timing switch mechanism of the present invention isherein disclosed as mounted upon or coupled with a picture projectingmachine of the type in which a number of picture plates are stacked in apredetermined position and are successively and periodically moved by anelectrically operated motor into projecting position. However, it is tobe understood that this timing switch mechanism is adaptable to manyother uses in connection with the periodic opening and closing of anelectric circuit and accordingly in showing and describing it inassociation with a picture projector there is no intention of limitingits use in this manner.

In the drawings the numeral In generally designates a still pictureprojecting machine ofa well known type designed for the projection ofpictures of 35 mm. size. This machine is provided with a manual lever Il whereby manual changing of the pictures may be accomplished if desiredor such changing of the pictures may be electrically effected by meansof a push button control, not shown, but which is connected with acurrent carrying cable 12, whereby an electric motor within the machine,when energized, effects the automatic transfer of a picture from a groupstacked in a receiver l3 upon the top of the machine, to a position forprojection through the lens barrel l5. Simultaneously with thisoperation, the picture previously on display, if any, is shifted into abottom receiver not shown. This mechanism is all of standard well knownconstruction and accordingly it is not believed that it requiresillustration or further description for proper understanding by thosefamiliar with still picture projectors of the type under consideration.

The body or housing of the machine has an outwardly and downwardlyextending bottom flange or skirt l6 and the machine stands on supportingfeet, not shown, so that the bottom edge of this flange is elevated fromthe underlying surface upon which the machine is supported. Themechanism of the present invention is mounted on an upstanding plate [8which is disposed at 3 one side of the projection machine as shown inFigure 1, and is secured in position by a clamp l9 which grips thebottom edge of the flange I6 as illustrated in Figure 3.

Secured to one face of the plate l8, which will be defined as the backface, is a synchronous motor which is generally designated and which hasa shaft 2| which is extended through the plate It to a substantialdistance beyond the front face thereof. This motor i of the type whichis suitably back geared to turn theshaft at one revolution per minute.

Secured to the shaft 2| at the front side of the mounting plate I8 is asleeve 22. This sleeve is maintained on the shaft against rotation bymeans of a set screw 23 or in any other suitable manner and at the backend of the sleeve is an encircling flange 24. The bore 25 of the sleeve22 is threaded at its forward end as indicated at 26 and the shaft 2|terminatesin thebore short of this threaded portion as shown in Figure4.

Mounted upon the sleeve 22 is a series of timing wheels 2i, three beinghere shown. These wheels are in abutting relation one with the other andthe rearmost one bears against the flange 24. The timing wheels aremaintained in place by the cap 28 which is centrally apertured to have ascrew 29 extended therethrough and threaded into the forward end of thebore 25 so that the cap 28 bears against the outermost timing wheel.

The timing wheels are provided around their peripheries with spacedspurs or teeth 21' and the spacing of the spurs upon each wheel isdifferent from that of the spurs on each of the other wheels.Accordingly one wheel may have two equally paced spurs and the nextwheel four and the next six or eight so that the wheels may function ashalf minute, quarter minute or sixth minute timing wheels for the switchhereinafter described.

By the provision of a number of these wheels having teeth at differentlyspaced intervals timing of the mechanism can be altered by changing thewheel to set up different groups thereof.

Disposed on one side of the timing wheels 21, here shown as upon theunderside thereof, are the two spaced parallel arms 30. These arms aresecured to the plate l8 and pass freely through the insulation body 3|of an electric circuit controlling switch which is generally designated32 and which is of a type having a pivotally mounted tongue or blade 33having one end curved upwardly as shown. This switch 32 is placed sothat the upwardly curved end of the switch blade 33 will be in the pathof movement of the teeth 21' of one of the wheels 21.

The switch 32 has the two terminals 34 for the connection of electricconductors 35 and 36 thereto, which conductors are put into electricalconnection when the tongue 33 is depressed.

Mounted upon the plate l8 below the switch 32 is a supporting body 31upon which is secured the platform 38. One end of this platform exoneend of the lever is positioned beneath the switch 32 to which it ispivotally coupled by means of the pivot bolt 43 and the cradle 44. Asshown this cradle receives the body of the switch 32 and the bolt 43 ispivotally connected to the bottom part of the cradle and to the adjacentend of the lever 4|.

The opposite or outer end of the lever 4| carries an upstanding post 45by means of which the oscillation of the lever about the pivot 42 isfacilitated. Beneath the lever 4| and directly below the post 45 is abutton 45 which is adapted to engagev in one of the depressions 40 whenthe lever is swung to any one of the three positions necessary forproperly locating the switch 32 beneath a selected toothed timing wheel21.

The cradle 44 is substantially U-shaped as shown in Figure 4, and thebody 3| of the switch 32 rests therein and is adapted to have slightsliding movement so that the necessary swinging of the cradle and theinner end of the lever 4| may take place while the switch moves in astraight line or path transversely of the lever.

The synchronous motor 20 includes the usual coil or winding C and theflow of electric current from the source to this motor and through theswitch 32 to the picture or slide changing motor of the projectormachine, is under the control of the toggle switch 46 which is mountedin a suitable convenient position, preferably upon the top of the platel8 as here illustrated.

In the circuit diagram forming Figure 6 the slide changer motor which ishoused within the machine ID, is diagrammatically illustrated anddesignated 41 and in this diagram the numeral 48 designates one of twoseparable couplings by means of which necessary current conductors arejoined together, the other one of the couplings being designated 48. Thecoupling 48 which has wire connections directly with the synchronousmotor 20, the switch 32 and the control switch 46 may be mounteddirectly uponthe side of the plate |8 as shown in Figure 2, while theother coupling section 48' is connected with the cables |2 which are inturn connected with the changer motor 41 and with the wires orconductors by which the current is fed in from a source and returned,such conductors being designated 49.

As will be readily seen upon reference to the circuit diagram, when theconductors are coupled together by the coupling units 48 and 48',electric current from the source will be carried to the terminal a whereit will be divided to flow through the conductors a, b, the conductor aleading to one side of the synchronous motor coil C and from the otherside of this coil through conductor 11 to a terminal a: of the switch46. The conductor 1) leads to a terminal y of the toggle switch 48. Asecond terminal b is electrically connected by conductor 35, with oneside of the normally open switch 32 and the other side of this switch isconnected by the conductor 36 with a terminal y of the toggle switch 46.The fourth terminal :0 of this toggle switch is connected by the returnconductor d with the third terminal 0 of the connector 48. When theparts 48 and 48 are connected together the terminal I) will beelectrically connected with the terminal b which is electricallyconnected with one side of the slide changer motor 41, the other side ofthe motor being connected to the return lead as illustrated. a

The switch 46 is of a type designed for the control of parallel circuitsand particularly of the slow-make, slow-break type such as thatillustrated in the patent to Krieger No. 2,133,545. This switch has acontrol or toggle arm 45' which actuates a pair of contactors e, e whichare electrically insulated from one another. The contactor 2electrically connects the terminals x, at and the contactor e"electrically connects the terminals y, y" when the arm 48 is oscillatedin one direction so as to simultaneously close the circuit through thesynchronous motor coil C and to prepare the circuit in which the switch32 is connected so that when the switch 32 is closed the slide changermotor will be energized.

As will be readily understood from the foregoing when the switch 46 isclosed the synchronous motor 20 Will be set into operation and thetiming wheels will be rotated at a speed of one revolution per minute.By actuating the pivoted lever 4| the switch 32 may be shifted in or outso as to bring it into desired position to be periodically closed by thespurs of the selected one of the wheels 21. Thus with the arrangementhere illustrated if the lever 4| is shifted in a direction to move theswitch 32 inwardly toward the plate IS the innermost wheel 21 having thetwo equidistantly spaced spurs 2'! will close the switch 32 at halfminute intervals. If the switch 32 is set in the center position wherethe switch blade will be periodically depressed by the spurs of thecenter wheel, which spurs are four in number and equidistantly spacedthen the switch 32 will be closed at quarter minute or fifteen secondintervals and the picture motor will be correspondingly operated tochange the pictures of the projector at such intervals.

We claim:

1. In an electric circuit timing switch, a substantially rectangularbody of an insulating material having a channel in its upper side, apair of opposed contact elements fixedly mounted in the side walls ofsaid channel toward an end thereof, a tongue of spring metal within saidchannel and having one end secured toward the opposite end of thechannel and its other end upwardly curved and overlying said contactelements, a shaft extending transversely of and above said body, rotaryelements mounted on said shaft and having their peripheries eachprovided with a series of spurs, and means for shifting said bodyrelatively to said rotary elements to selectively position said tonguein the paths of movement of the spurs, whereby the curved end of thetongue will be depressed into bridging relation with respect to saidcontact elements, the spurs on each of said rotary elements beingdifferently spaced to vary the timing operation of the spring tongue.

2. In a still picture projector, including its casing and an electricmotor operated slide changer, a bracket adapted to be detachably mountedon said casing, a plate supported vertically on said bracket, ahorizontal platform mounted on the outer side of said plate toward itslower end, a laterally shiftable member mounted on the upper side ofsaid platform, a body of an insulating material supported on saidshiftable member and having a channel in its top side extending parallelto said plate, a pair of opposed contact elements mounted in the sidewalls of said channel toward an end thereof, a tongue of spring metalwithin said channel and having one end secured toward the opposite endof the channel and its other end upwardly curved and overlying saidcontact elements, an electric motor mounted on the inner side of saidplate and having its shaft extending through the plate above said body,rotary elements mounted on the extended end of said shaft and havingtheir peripheries each provided with a series of spurs, and a hand leverfor moving said shiftable member and said body relatively to said rotaryelements to selectively position said tongue in the paths of movement ofthe spurs, whereby the curved end of said tongue will be depressed intobridging relation with respect to said contact elements, the spurs oneach of said rotary elements being differently spaced to vary the timingoperation of said spring tongue.

CLARENCE J. CADWELL. FRANK M. ADAMSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,984,302 De Vries Dec. 11, 19342,360,179 Urbas et a1. Oct. 10, 1944 2,371,378 Clark Mar. 13, 1945

